News

The real rat race

By Katynna Gill

16 June 2011

Dr Grainne Cleary, from the School of Biological Sciences, holds a native bush rat, Bogul. Associate Professor Peter Banks and Dr Grainne Cleary are leading a Bogul reintroduction project in bushland around Sydney Harbour in July.

Sydneysiders sometimes feel swept up in the rat race, but there's a real rat race coming to bushland around Sydney Harbour, when University of Sydney ecologists introduce populations of native bush rats, called Boguls, to bushland locations in July. The new Bogul populations will not only reinstate a native species to these areas, but also potentially reduce the populations of pest black rats as the Boguls compete for territory and resources.

Boguls (Rattus fuscipes) are native to Australia and were once common in Sydney, but were wiped out when Europeans settled the area. Research led by Associate Professor Peter Banks and Dr Grainne Cleary, from the University of Sydney's School of Biological Sciences, suggests that Boguls may be able to out-compete black rats (Rattus rattus) in the race for territory.

"This re-introduction of Boguls in July will be the first large scale trial to see how well the Boguls can compete against pest black rats. We will give the true blue Bogul back its residence advantage by reducing black rat numbers, but that is all we can do - the rest is up to our little Aussie battler Bogul to fight for its traditional territory," said Dr Grainne Cleary.

The reintroduction project is led by the University of Sydney team and supported by Taronga Zoo, National Parks and Wildlife Service, Mosman Council, Australian Wildlife Conservancy and Rentokil Pest Control.

Research by one of Associate Professor Peter Banks' previous PhD students on Bogul populations in bushland in Jervis Bay indicated that when black rat numbers were reduced, Boguls were able to move in from adjacent areas and establish populations. Checking these areas five years later found that the Boguls had maintained strong populations, while black rat numbers remained very low.

"We're keen to see whether the Bogul is in fact able to out-compete the black rat, as suggested by the work in Jervis Bay and another pilot study we conducted in an enclosure of natural bushland at Taronga Zoo in 2010," explained Associate Professor Banks.

"The trial starting in July will take place in sixteen bushland locations from Mosman to Manly. We'll be releasing a hundred Boguls, caught from outer Sydney bushland, into our national park test sites to measure their success in out-competing the pest black rats," said Associate Professor Banks.

"The Boguls will be microchipped and radio tracked to chart their movements over the next eighteen months as part of the project."

So how can Sydney residents, especially those in the Mosman and Manly areas, tell the difference between their new Bogul neighbours and the pest black rat?

"The most obvious difference is the length of the tail: pest black rats have tails that are much longer than their bodies, whereas Boguls have tails that are the same length as their bodies or even shorter," said Dr Cleary.

"Apart from the tail length, most people find it difficult to tell the two apart. Despite the name, black rats aren't actually black! They are a similar grey colour to Boguls, so it's easy to mistake them. We hope local residents will take a close look to identify Boguls and help keep them safe," explained Dr Cleary.

"It'd be great if local residents in the Mosman and Manly areas could help by keeping their cats indoors overnight, to give our native Boguls the best chance at success."

Taronga Zoo's Education Centre staff will also be working to get local students and schools involved with many aspects of the research project and to raise awareness for and support of the native Boguls.

"There's no need for residents to fear the Boguls invading their homes: the native bush rats do as their name suggests - they stay in the bush!" said Dr Cleary.

"Interestingly, Mosman residents have been trying to tell the difference between Boguls and pest black rats since the 1800s! We found a research paper from 1897 written by a zoologist at the Australian Museum about his encounter in his Mosman house with what he thought were native Boguls, and including comments from other residents in Mosman, North Sydney, the Inner West and Eastern Suburbs. Unfortunately, it turns out they were looking at black rats, as noted at the end of the paper by another Fellow of the Zoological Society of London," said Associate Professor Banks.

"Finally after over 100 years of this rat race, we're doing something about it by giving the Boguls a helping hand! By re-introducing the Boguls around Sydney Harbour, which will hopefully reduce the population of black rats, there is fantastic potential to improve the entire ecosystem in the area and also possibly see the return of other native species such as bandicoots and gliders."